Y4 - Paediatric Diabetes Flashcards
What are the types of diabetes that affect children?
Type 1 (most common) Type 2 Monogenic diabetes (MODY) Secondary diabetes, e.g. CF related diabetes Neonatal diabetes (transient/persistent)
In which groups of people is T2DM more common?
Afro-Caribbean or Asian ethnicities
What causes MODY?
Autosomal dominant kind of non-ketotic diabetes in childhood/young adults
6+ causal genes exist
MODY is caused by SINGLE gene defects
What are the key features of MODY?
Diagnosed <25y
Having parent with DM with DM in two or more generations
Not necessarily needing insulin
What are the most common types of MODY gene mutations?
HNF-1a (70%)
HNF-4a
HNF-1b
Glucokinase
HNF1-a MODY (MODY3)
Defect on chromosome 12 that leads to progressive decrease in insulin production
Features severe hyperglycaemia after puberty
Diabetic retinopathy and nephropathy often occur
Rx: sulphonylureas
HNF4-a MODY
Generally Rx with SU but may progress to needing insulin
Rare
HNF1-b (MODY5)
Diabetes associated with renal cysts, uterine abnormalities, gout
Usually need insulin Rx
Glucokinase (MODY2)
No Rx required
Blood sugars usually only slightly elevated
Caused by mutation on glucokinase gene (chromosome 7)
What is the role of glucokinase?
Coverts glucose into glucose-6-phosphate, which is needed to stimulate insulin secretion from beta-cells
How does MODY differ from T1/T2DM?
Caused by a single gene, as opposed to T1/T2 which is caused by polygenic and environmental causes
Why is molecular diagnosis in MODY so important?
It has consequences for diagnosis, family screening & management
What does testing for MODY involve?
Having blood taken for pancreatic antibodies
Blood/urine tested for C-peptide
Blood for genetic testing
What does MODY stand for?
Maturity onset diabetes of the young
What is the pathogenesis of CF related diabetes?
Mutation of the CFTR gene leads to two things:
1. Increased infections (and release of inflammatory markers, e.g. TNF) and increased use of steroids leads to increased insulin resistance
- Thick secretions block the pancreatic duct –> fatty infiltration and fibrosis of pancreatic islet cells –> decreased insulin secretion
Both of these lead to hyperglycaemia
Describe the onset of CFRD
Gradual onset
Usually around 18-25y
In which patients is CFRD most common?
Those with homozygous Phe508del mutation of CFTR
How are children with CF screened for CFRD?
Annual screen for CFRD using OGTT by age 10 in patients with CF (without CFRD)
Annual review for complications after 5y of diagnosis of CFRD
How is CFRD treated?
Insulin
What is involved in the aetiology of T1DM?
Genetic susceptibility
Autoimmunity (T cell mediated destruction of pancreatic beta-cells)
Environment - i.e. viral trigger
What gene in particular is implicated in T1DM?
Insulin-dependent diabetes mellitus 1 gene locus
part of HLA DR/DQ locus on the major histocompatibility complex
How likely are you to get T1 diabetes if your identical twins has it?
50%
How likely are you to get T1 diabetes if your fraternal twin as it?
11%
Where is the incidence of T1DM highest? And why might this be significant?
UK, Finland, Sweden etc.
All on same latitude therefore may be correlation between vitamin D and T1DM
Describe the natural history of T1DM
Genetically susceptible individual is exposed to an environmental trigger
There is subclinical reduction in beta-cells
Symptoms appear after B-cell numbers have dropped significantly
(so there are several months after trigger where individual is symptom free)
What is the typical presentation of T1DM?
Polyuria Polydipsia Weight loss Fatigue Abdominal pain (due to ketone build up)
DKA (around 25%)
What factors make presentation of T1DM with DKA more common?
Younger age Diagnostic error Ethnic minority Lower BMI Preceding infection Lower socio-economic status Unemployed mother
What factors make presentation of T1DM with DKA less likely?
FH of T1DM
Higher parental education
Higher background incidence of T1DM
Presence of structured diabetes team
What things are involved in managing the newly diagnosed T1 diabetic?
Advice re. exercise & health eating, insulin injections, hyperglycaemia and ketones, carb counting, glucose testing, hypos, insulin jumps, DKA
Give examples of insulin regimens
Twice daily pre-mixed insulin
Basal bolus insulin
Carb counting
Insulin pump
What does the twice daily pre-mixed insulin regimen involve?
Give starting dose of 0.5 units per kg
2/3 dose in morning pre-breakfast
1/3 dose pre-dinner
Adjusted according to blood glucose levels
What does the basal bolus regimen involve?
Three doses of novorapid with breakfast, lunch & dinner
Long acting insulin at night before bed (e.g. Levemir)
What must you educate parents about carb counting?
Identifying carbs in food
Calculating carbs in foods (labels, working out portion sizes etc.)
Teach insulin to carb ratios
How to correct if BG above target
What does the insulin pump have to help with calculating doses?
Automated bolus calculator
How does the pump give insulin?
Programmed background basal rate
Bolus doses
Define hypoglycaemia
BG <4
What are the symptoms of hypos?
Anxiety/irritability Shaking Sweating Tachycardia Dizziness Hunger Blurred vision Weakness/fatigue Headache
How do you Rx a mild hypo?
Fast acting sugar (fruit juice, fizzy drinks, sweets, glucose tabs)
Recheck bloods in 10 minutes
If still <4 repeat dose of fast acting sugar
If >4 & <1h to next meal - no carbs; 1-2h to next meal take 10g carb; >2h to next meal take 20g carb
How do you manage a moderate hypo where the child is unable to swallow?
Administer glucose gel into buccal mucosa
How do you treat a severe hypo (child unconscious/fitting)?
IM glucagon
Call 999
What does IM glucagon do?
Mobilises hepatic glucose
What is the major SE of IM glucagon?
Severe vomiting
How would you manage a severe hypo in hospital?
IV access - give glucose 5ml/kg 10% or by rectal tube if no IV access
With glucagon 0.5-1mg IM or slowly IV
Expect quick return to consciousness, if not recheck glucose, if low give dexamethasone IV
If slow return to consciousness after severe hypo but normal BG now, what must you consider?
May have having post-ictal symptoms after a hypoglycaemic fit
What are the symptoms of hyperglycaemia?
Extreme thirst Hunger Polyuria Dry skin Blurred vision Drowsy Slow healing wounds
What does DKA result from?
Deficiency of insulin and often increased levels of counter-regulatory hormones (e.g. catecholamines, glucagon, cortisol, growth hormone) e.g. due to sepsis
What is the biggest concern with DKA in children (which is less common in adult DKA)?
Cerebral oedema
What are other fatal events that can occur in DKAs?
Hypokalaemia
Aspiration pneumonia
How do you prevent aspiration pneumonia in someone having a DKA?
NGT if semi-conscious to protect airway
What are the clinical features of DKA?
Listlessness Confusion Vomiting Polyuria Polydypsia Weight loss Abdominal pain Dehydration Kussmaul breathing Pear drop breath Shock Drowsiness Coma
When should you check for ketones?
If BG is >15mmol/l
What is kussmaul breathing?
Deep and laboured breathing in an attempt to reduce CO2 in the blood
What are the 6 things patients are told to look out for in DKA?
Persistent vomiting >4h Heavy or rapid breathing Abdominal pain Moderate/severe dehydration High BG (>17)
What is the triad of DKA required for diagnosis?
Hyperglycaemia (11mmol/L+) Acidosis - Mild pH <7.3 - Mod pH <7.2 - Severe pH <7.1 Ketones (in urine/blood)
How do you manage DKA?
ABC
If shocked give fluid bolus 10mls/kg & reassess
IV fluids (normal saline & KCl)
Start insulin infusion 1-2h after fluid starts
What is your aim for DKA management?
Slow drop in BG of 5mmols/hour
Start insulin at 0.1u/kg/h
What Ix do you want to do in DKA?
Hourly BG 2-4hrly blood gases and electrolytes Hourly neuro obs (cerebral oedema risk) May want to do ECG Weighing Infection screen (sepsis may cause DKA)
What must children with T1DM always carry around with them?
Blood sugar meter and hypo kit
What is HbA1c?
Glycosylated haemoglobin
Gives an idea of BG control over lifespan of a RBC (120 days)
Higher HbA1c correlates with higher incidence of diabetic complications
When should you stop giving insulin in a patient with DKA?
Once blood ketone levels <1 & patient able to tolerate food
Give s/c insulin, feed patient
Stop insulin infusion 10-60m after s/c insulin injection
What symptoms may indicate cerebral oedema?
Headache or behaviour change
In which people is cerebral oedema most common?
In children
Especially those who have had a rapid fall in glucose or sodium
What should you do if you suspect infection in DKA?
MSU, blood culture, CXR
Start BS antibiotics
